Usha Vijayraghavan (seated) with a student in a greenhouse

New Delhi, Feb. 19: Indian scientists have identified and manipulated a gene in rice plants that can dramatically alter the flowering time of rice, a feat that may lead to fast-maturing and high-yielding plants.

A research team led by Usha Vijayraghavan at the Indian Institute of Science (IISc), Bangalore, has pinpointed a gene that controls two critical features of rice plants — flowering time and plant architecture.

“Both traits are immensely useful in controlling the yield from a plant,” Vijayraghavan, associate professor at the IISc department of microbiology and cell biology, said.

The scientists have shown through laboratory and greenhouse studies that the gene, called RFL, can be used to delay or hasten flowering time of rice plants, which occurs shortly before maturity.

Reducing the activity of the RFL gene delays flowering of the plants, while increasing its activity shortens flowering time, the team said. Their findings appeared today in the Proceedings of the National Academy of Sciences.

The rice variety tested at the IISc has a typical flowering time of 90 days, but in the genetically manipulated versions of the plant with the highest activity of the RFL gene, flowering occurred in about 45 days.

The RFL gene can also change plant architecture, allowing side shoots to sprout from the main stem which may translate into more flowers, more grain, and possibly more grain yield per plant.

“This could be a step towards producing varieties of rice that mature early and yield more grain,” said Akhilesh Tyagi, a plant biologist at the University of South Delhi and coordinator of India’s rice genomics programme.

“But the genetic modifications would need to be tested in different environments and with appropriate rice varieties,” he said.

But Vijayraghavan cautioned that scientific challenges needed to be tackled before the RFL gene could be used as a yield-enhancing tool. “We don’t have a magical solution yet,” she said.

Uncontrolled activity of this gene may lead to negative effects and depress the grain yield per plant, she said. “We need to find a way to switch the gene on at the right place at the right time and shut it off.”